From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51EC5C33CAF for ; Thu, 16 Jan 2020 17:58:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E62D2073A for ; Thu, 16 Jan 2020 17:58:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="jazQCFCK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394680AbgAPR6i (ORCPT ); Thu, 16 Jan 2020 12:58:38 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:12220 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394598AbgAPR63 (ORCPT ); Thu, 16 Jan 2020 12:58:29 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 47zBkp72vRz9v0MY; Thu, 16 Jan 2020 18:58:26 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=jazQCFCK; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id sWc84WilRORj; Thu, 16 Jan 2020 18:58:26 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 47zBkp5myMz9v0MW; Thu, 16 Jan 2020 18:58:26 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1579197506; bh=B22u4TdOal01xxsjkrua7iGmnqsKQfjsari1Wci2wQA=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=jazQCFCKPDea5lYh2KgxAvOfg212DshtdG+JTeONviEiCNy0Rb1UeHG2HitQrkZta dph9+c7i0zIG8Jmr7NFpb7OgHOnMdwyB7SSii7h7rc1yCgtyKb8alaGGzLoYDhGQpU FC96U2rCRgY7UBaJdLOtZ1YGEFTk/Ou6UTLHKcpQ= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 5395C8B82D; Thu, 16 Jan 2020 18:58:28 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id l9JgyIsIeLnb; Thu, 16 Jan 2020 18:58:28 +0100 (CET) Received: from po14934vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 93F048B82E; Thu, 16 Jan 2020 18:58:27 +0100 (CET) Received: by po14934vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 6D22D64A35; Thu, 16 Jan 2020 17:58:27 +0000 (UTC) Message-Id: <7ac2f0d21652f95e2bbdfa6bd514ae6c7caf53ab.1579196675.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [RFC PATCH v4 03/11] lib: vdso: only read hrtimer_res when needed in __cvdso_clock_getres() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, x86@kernel.org Date: Thu, 16 Jan 2020 17:58:27 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Only perform READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res) for HRES and RAW clocks. Signed-off-by: Christophe Leroy --- lib/vdso/gettimeofday.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 9563be3cb5fa..8b3084d9a3ec 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -326,7 +326,6 @@ static __maybe_unused int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) { const struct vdso_data *vd = __arch_get_vdso_data(); - u64 hrtimer_res; u32 msk; u64 ns; @@ -338,7 +337,6 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) vd->clock_mode == VDSO_CLOCKMODE_TIMENS) vd = __arch_get_timens_vdso_data(); - hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); /* * Convert the clockid to a bitmask and use it to check which * clocks are handled in the VDSO directly. @@ -348,7 +346,7 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) /* * Preserves the behaviour of posix_get_hrtimer_res(). */ - ns = hrtimer_res; + ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); } else if (msk & VDSO_COARSE) { /* * Preserves the behaviour of posix_get_coarse_res(). -- 2.13.3